1969 L-71 427/435 power steering conversion

[Kenneth K.]

Re: 1969 L-71 427/435 power steering conversion

Joe-

It amazes me how much knowledge you have about these old cars! Thank you for sharing this. So much appreciated.

That’s a relief the 3829193 pulley will work. I really tried to figure it out myself but my internet searches lead no where. Thanks again.

When I saw the diagram in the AIM that showed the capture belt my first thought was “how the heck do you get the belt on without an adjustment”. I’ll be pulling my engine later this fall to detail it and the engine compartment so that will be a perfect time to tackle the belt.

Ken

[Kenneth K.]

Re: 1969 L-71 427/435 power steering conversion

Joe-

What is the purpose of the capture belt? It seems redundant so is it a safety in case the main belt from the balancer-PS/alt-water pump fails?

[Joe L.]

Re: 1969 L-71 427/435 power steering conversion

Joe-

What is the purpose of the capture belt? It seems redundant so is it a safety in case the main belt from the balancer-PS/alt-water pump fails?

Kenneth------


I can only speculate on the reasons that Chevrolet engineers decided the captive belt was necessary. However, my guess is that they determined that the waterpump drive required a 2 belt drive. No Corvette big block waterpump, 1965-74, was ever driven by a single belt.

Want to make installation of the captured belt unnecessary and still have the 2 belt drive? Simply install an idler pulley as was used for 1968-74 big blocks with C-60. This makes for a 3 point belt installation with adjustment at the idler pulley.

[Larry E.]

Re: 1969 L-71 427/435 power steering conversion

My guess would be that the engineers knew that this engine would be Amateur

raced like Drag/Gymkhana/and etc..
By doing this(Just like "Deep Grove" Pulleys) would add some insurance/reliabiltiy to the sport. JMHO>Larry

[Peter M.]

Re: 1969 L-71 427/435 power steering conversion

Ken,
My guess is that because air conditioned big block compressors were driven solely by the water pump pulley multiple additional belts would be needed to prevent slippage.
Kind regards.

[Kenneth K.]

Re: 1969 L-71 427/435 power steering conversion

Interesting that no BB water pump was ever driven by a single belt. Even those BBs that AC was not an option, i.e. L-71, L-88 and ZL-1. I assume the L-88 and ZL-1 were also equipped with the captive belt. Since these cars were mostly drag raced the captive belt must have been considered essential.

Did you see the article in the last issue (12.23) of Hot Rod Magazine? They reprinted an article from 1968 that details the ZL-1 engine. Very cool. Joe- what did you do with the ZL-1 engine that you built? Do you still have it? Jack Cheskaty belongs to my local car club and lives about 1 mile from me. He bought the white ZL-1 new in 1969. He said he was 25 years old when he bought the car, single and a young engineer with lots of disposable income. He drag raced it for one year then sold it.

Ken

[Joe L.]

Re: 1969 L-71 427/435 power steering conversion

Interesting that no BB water pump was ever driven by a single belt. Even those BBs that AC was not an option, i.e. L-71, L-88 and ZL-1. I assume the L-88 and ZL-1 were also equipped with the captive belt. Since these cars were mostly drag raced the captive belt must have been considered essential.

Did you see the article in the last issue (12.23) of Hot Rod Magazine? They reprinted an article from 1968 that details the ZL-1 engine. Very cool. Joe- what did you do with the ZL-1 engine that you built? Do you still have it? Jack Cheskaty belongs to my local car club and lives about 1 mile from me. He bought the white ZL-1 new in 1969. He said he was 25 years old when he bought the car, single and a young engineer with lots of disposable income. He drag raced it for one year then sold it.

Ken

Kenneth------


Yes, L-71, L-88, and ZL-1 were all fitted with the captive belt. The cast iron balancer pulley, GM #3863108 is shown below. Some L-71 and all L-88/ZL-1 were fitted with this pulley.

GM#3863108.jpg

The "ZL-1" engine I built is not built to the same specs as the original ZL-1. It includes the GM re-released ZL-1 block and GM aluminum heads. However, internally, I built it to be streetable. Thus, lower compression and a GM hydraulic roller cam. The re-released ZL-1 block was modified to accept a roller cam which makes it very nice as a retrofit roller cam does not need to be used. I have installed this engine in my original owner1969 convertible for use "until I get tired of it". I also installed a brand new M-22 transmission that I assembled from all NOS GM components that I purchased over 40 years ago. Although I have installed the engine and transmission in the car, I have not even fired the engine for the first time, let alone driven the car with it. Don't ask me why as I'll say in advance, I have no answer. Photos of the engine and a few photos of the roller lifter installation below:

IMG_3869.jpgIMG_3871.jpgIMG_3993.jpgIMG_3994.jpgIMG_3995.jpg

Some photos of my original engine which I rebuilt/restored some time ago and never (AS YET) re-installed in the car are shown below. Someday, it will replace the ZL-1. Note the retrofit hydraulic rollers. As I've said many times before, I'd NEVER AGAIN build an engine with a flat tappet, hydraulic or mechanical, even though I have many, original NOS GM flat tappet cams in my collection [none for sale].

IMG_3881.jpgIMG_3880.jpgIMG_3879.jpg

[Kenneth K.]

Re: 1969 L-71 427/435 power steering conversion

Joe-

Your ZL-1 engine is absolutely beautiful and will sounds every bit as good as it looks. Hope you get it running soon so you can enjoy it. If you don’t someone else will! I gave Jack Cheskaty my issue of HRM with the 1968 reprint of the ZL-1 engine. As he paged through the article and saw the pictures he immediately said “did you see the exhaust”? I said you mean the round ports? No he said the exhaust manifold. I replaced the stock exhaust manifold with …(can’t remember the name) and it really opened her up… Joe- do you have the stock exhaust manifold on your ZL-1?

It looks like from the picture that your L-71 paint is on the red side. Is that true or is it the standard Chevy orange? The reason I ask is because my original paint on my L-71 looked to be to be on the red side. I have since painted it the standard Chevy orange but I always wondered about that.

Thanks for sharing your pictures. Very cool.
Ken

[Joe L.]

Re: 1969 L-71 427/435 power steering conversion

Joe-

Your ZL-1 engine is absolutely beautiful and will sounds every bit as good as it looks. Hope you get it running soon so you can enjoy it. If you don’t someone else will! I gave Jack Cheskaty my issue of HRM with the 1968 reprint of the ZL-1 engine. As he paged through the article and saw the pictures he immediately said “did you see the exhaust”? I said you mean the round ports? No he said the exhaust manifold. I replaced the stock exhaust manifold with …(can’t remember the name) and it really opened her up… Joe- do you have the stock exhaust manifold on your ZL-1?

It looks like from the picture that your L-71 paint is on the red side. Is that true or is it the standard Chevy orange? The reason I ask is because my original paint on my L-71 looked to be to be on the red side. I have since painted it the standard Chevy orange but I always wondered about that.

Thanks for sharing your pictures. Very cool.
Ken

Ken------

The exhaust manifolds on my "ZL-1" are stock, cast iron manifolds, the same as used on all other 1969 Corvette big blocks. By the way, the intake manifold is a GM #3963569 which was originally used on 1970 Chevelle LS-6 (without the runner numbers)and 1971 Corvette LS-6 (while known as the "LS-6" manifold, it was also used on 1970-72 L-78 in Chevelle, Camaro, and Chevy II). It's the only dual plane, rectangular port manifold ever made, GM or aftermarket, that will fit under a 1968-72 standard big block hood. It's probably my favorite manifold of all time.

IMG_3998.jpg

As far as the original engine paint goes, it's actually much too orange and not enough red. 1969 small block engine color, particularly for those assembled at Flint, had much more red in it than orange. The photos shown below are of my original valve covers which were removed from the engine in 1970 to replace with the L-46 aluminum covers. These photos very accurately depict the original color. Once-upon-a-time I made an informal study of Flint assembled, 1969 small blocks seen in various Chevrolet models with obviously original engines in wrecking yards. All were exactly the same color as mine. 1970 models were, too.

I selected the engine paint I used based on the low gloss sheen. I purchased and test sprayed at least 20 other engine paints on the market and most were WAY TOO glossy. Most were way too orange, too. So, I selected the one I used mostly on the basis of sheen. I also observed that the engine paint of big blocks of the same period was much more orange with practically no red in it, at all. I surmise that Tonawanda used a different paint supplier than Flint and neither supplier was held to a precise standard. Also, as you can see from my photos, the paint was not very durable, either, given all of the bare spots seen on these valve covers after less than a year of use and very careful, boxed storage before these photos were taken.

As I've mentioned previously, my distinct recollection of the engine paint on C2 small blocks was much more red than most folks think of as original today and very similar to the color of my original engine.

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[Kenneth K.]

[Chris H.]

Re: 1969 L-71 427/435 power steering conversion

Joe, beautiful ZL1. Just curious, what compression ratio and what are the specs of the cam? I presume you’re running hydraulic versus solid rollers? Thanks, Chris

[Joe L.]

Re: 1969 L-71 427/435 power steering conversion

Hi Joe-

i also have an LS-6 manifold but with my 850 double pumper there is less than 2 inches of space for an air filter under my BB hood. I have the tri-power installed on the engine and have no plans to replace it with the LS-6 manifold but just curious do you know what air filter would work with the 850 double pumper? What carburetor and filter are you planning on installing on your ZL-1?

Interesting the difference in colors between the two assembly plants. Not sure what color to paint my BB now that you said they were orange. I am absolutely sure my original engine paint color had some red in it but obviously I have no way to match the original color. What paint would you recommend I use? Rattle can is fine or I can spray it on…

Ken

Ken------


I'm using a new Holley R4802A which was the 1971 LS-6 carburetor. I'll be using the more-or-less standard 68-70 "drop down base" air cleaner.


I can't help much on the paint since it's been so long since I evaluated them and there are probably many different, and possibly better, products out there now. I chose the Bill Hirsch supplied Chevrolet orange primarily for the sheen level. No other paint I evaluated then had the proper sheen. Absolutely NO original Chevrolet engine paint was high gloss and whenever I see high gloss engine paints, I'm critical of them.

[Joe L.]

Re: 1969 L-71 427/435 power steering conversion

Joe, beautiful ZL1. Just curious, what compression ratio and what are the specs of the cam? I presume you’re running hydraulic versus solid rollers? Thanks, Chris

Chris------

My compression ratio is 9:1. Big blocks with high compression often suffer from detonation problems. I know; once-upon-a-time I owned two of them in Chevelles. I ABSOLUTELY DO NOT WANT ANOTHER ONE. I'll gladly sacrifice some potential power to avoid even the possibility of having that problem again. This engine as it is will have way more power than I'll EVER use. I don't get involved in racing competition and I drive SANELY on the road.

Cam is a GM #12366543. Duration @ 0.050"= 224/234

lift= 0.527"/0.544"

hydraulic roller. I'd NEVER use a mechanical roller for street operation. NEVER. EVER.

A few engine build photos:


IMG_3999.jpgIMG_4001.jpgIMG_4002.jpgIMG_4003.jpgIMG_4004.jpgIMG_4005.jpgIMG_4006.jpg

[Larry E.]

Re: 1969 L-71 427/435 power steering conversion

Joe>Beautiful Engines; so much detail!! Larry

[Chris H.]

Re: 1969 L-71 427/435 power steering conversion

Joe, ah the ZZ427/502 cam, a very nice street cam. I like the main bear caps with "ZL1" on them and the use of studs. Very trick. Curious, is that a windage tray? Is it a GM part?